People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Sweet Dreams Are Made Of This: What's A Good Night Of Sleep, And How Do You Get It?

We need sleep. It’s absolutely essential for our physical and mental well-being. With that said, it’s important to make sure you’re doing it right. I recently had the opportunity to speak with Dr. Andrew J. Westwood, assistant professor of Clinical Neurology Division of Epilepsy and Sleep Disorder at Columbia University Medical Center in New York City, in order to figure out what a perfect night of sleep actually was and how one could get it.

How Many Hours Of Sleep Do We Really Need?

When it comes to getting a good night of sleep, sleep quality takes precedence over sleep quantity.

“If you can function during the day, then you’re getting enough sleep,” Westwood said. “The average person needs usually between seven and eight hours of sleep, but everyone is different. If you feel fine and can function well during the day on three hours of sleep, then you don’t need to worry.”

Many times the sleep specialist meets patients who believe they have insomnia but actually turn out to be a short sleeper — that is, a person who regularly sleeps less than the average amount for his age group.

These individuals have no problem functioning and don’t feel sleepy even on as little as three hours of sleep a night. They are often thought to be more successful, but before you go ahead trying to change your sleep pattern, know that you can’t just become a short sleeper. They are simply born that way. Westwood also dispelled the old wives' tale that the older one gets, the less sleep one needs.

“The message that as you get older you need less sleep, that’s not true. Usually people will sleep the same amount of hours during a 24-hour period,” Westwood said.

According to Westwood, older people do tend to have more difficulty falling asleep and staying asleep. This may cause them to sleep in chunks throughout the day. Still, they will usually rack up the same amount of sleep hours in a 24-hour period as they always have throughout their entire adult life.

What Causes Insomnia And How Do You Treat It?

Insomnia is a vicious cycle. You can’t fall asleep. This causes you to worry about not falling alseep. In turn, all this anxiety makes it even more difficult to fall asleep. “It becomes a self-fulfilling prophecy,” Westwood said.

Still, there is good news: “If someone suffers from acute insomnia, one of the things that is really important is to reassure them that they slept before and they are going to sleep again.”

Hypersensitivity is at the root of most cases of insomnia. An individual becomes disrupted by something such as a pet or a car outside and is unable to fall back asleep. Westwood advises that in these circumstances the sleeper try to ensure he falls asleep in a cool, quiet environment, and ear plugs may help.

As explained earlier, not everyone needs as many hours of sleep as they may believe, and most often even if they are not sleeping perfectly, they will be able to survive the next day without too much trouble.

“When that day is over, they will realize that the catastrophe really didn’t come about,” Westwood said.

Westwood added that while medicinal approaches for insomnia do work in the short run, in order to try and solve the problem, you need to address the underlying condition. One of the most useful techniques a sleep specialist will use to do this is cognitive behavioral therapy.

When Should Snoring Become A Concern?

Snoring is as widespread as it is annoying. According to Mayo Clinic, it affects nearly half of the adult population. Snoring occurs when air flows past relaxed tissues in your throat and causes them to vibrate as you breathe.

“If you’re getting sufficient sleep but still wake up sleepy with morning headaches, you should see a sleep specialist,” Westwood said. These symptoms may be a sign of sleep apnea, a sometimes dangerous condition.

Sleep apnea, unlike regular snoring, will cause the airways to become completely blocked. This leads to periods of time when the sleeper is completely deprived of oxygen, which thus leads to decreased levels of oxygen in the sleeper's blood. These low oxygen levels may lead to a variety of health conditions, including increased risk of heart conditions and stroke, and increased chances of developing high blood pressure. A sleep study is the only way to diagnose sleep apnea, according to Westwood, but once diagnosed, the condition is usually quite easily treated.

Sleep apnea can be alleviated through lifestyle changes and medical intervention. For example, according to the UK’s National Health Service, losing weight and maintaining a healthy body weight will reduce the fat in your neck that squeezes the airways shut. Reducing alcohol intake and cigarette use or giving them up all together may also be helpful.

What's The Best Position To Sleep In?

“The best sleep position for you is the sleep position you can sleep in,” Westwood said.

Unfortunately, some people are limited in their number of sleeping positions by either pain or difficulty breathing. For those suffering from sleep apnea, sleeping on your back may be best to help keep the airways clear. Dr. Hooman Melamed, an orthopedic spine surgeon at the DISC Sports & Spine Center in Los Angeles, Calif., explained that this position will also align one’s head, neck, and spine, Medical Daily reported.

Sleeping on one’s side has also been shown to be helpful for those with sleep apnea because it also keeps the airways opening, For those who suffer from acid reflux, sleeping on your left side may prove particularly helpful, a claim which was demonstrated in a 1994 study.

What Are The Rules Of Daytime Napping?

Sometimes you just need a nap. A 1995 study conducted by NASA showed that 26 minutes of sleep improved performance by 24 percent and alertness by 54 percent. The participants also felt that their memory had improved and they felt less tired.

“Sleep after learning something can help you to better remember, and you will learn more efficiently that way,” Westwood said, adding that “naps for short periods of time can be really helpful to ward off the sleepiness feeling experienced with hypersomnia.”

Unfortunately, not all napping is good, and a recent study from Cambridge University found a scary correlation between taking a napping for longer than an hour and increased chances of early death. The study followed 16,000 participants for 13 years and found that those who napped for more than an hour a day were at greater risk of heart disease, cancer, and respiratory illnesses. However, although the study showed a link between daytime napping and disease, it failed to prove causation.

Still, Westwood explained that there are other health risks that may be associated with daytime snoozes. “The longer you nap, the more likely you are to be in deep sleep, and when awoken, you can experience sleep inertia.”

Sleep inertia occurs when you are awoken as your brain starts to shut down the cognitive processes you were meant to charge. It can leave you lacking fine motor control, and according Westwood, can make you feel “even worse than before you went to sleep.”